This invention is related to the field of satellite communications and particularly directed to an apparatus for interfacing time division multiplex signals provided by data gathering codecs with an FDM/TDM processor as disclosed in co-pending U.S. Patent Application Ser. No. 849,584 now U.S. Pat. No. 4,199,660. The FDM/TDM processor is becoming an increasingly important part of communications sytems implementation in both terrestrial and space communications. The FDM/TDM processor according to the co-pending application is a 60 channel unit while commercially available data gathering PCM codecs (such as Ericsson ZAK 30/52) are 30 channels each. The codecs operate on serial, compressed, sign magnitude data while the FDM/TDM processor operates on parallel, linear, 2's complement data.
Various techniques of interfacing serial and parallel systems are generally known in the communications art. Picquendar (U.S. Pat. No. 4,103,110) uses registers to convert PCM serial data into parallel data, and a transmultiplexer for converting parallel data to serial. Melindo et al (U.S. Pat. No. 3,914,553) uses orthogonal matrices to convert serial to parallel data in a PCM/TDM terminal. Shift registers are used in the orthogonal matrices as conversion units.